Storage racks of the type comprising a plurality of shelves identifying compartments in which elements are to be stored in the form of packages such as cases, boxes, baskets, etc. supported by pallets and which are termed generally load units are known. Handling of the elements from and to the cells of the storage rack or warehouse is performed by lift devices which traverse on tracks along the shelving and have fork means for raising and depositing of the pallets.
Ordinarily the load units cannot be directly stacked to avoid damaging them and because this procedure would give rise to the problem of withdrawal from the warehouse of those load units not located on the top of each stack. It is therefore normal to follow the procedure of using a compartment for each load unit or at most for load units side by side.
To optimize space utilization in the warehouse it is therefore preferable that the space between superposed shelves be just higher than the load unit so that the space between the top of a load unit and the shelf above be minimal. This can be easily provided if the load units are all of the same predetermined height or are in a limited quantity of standard heights and in a foreseeable number so that the warehouse can be laid out in advance with appropriately spaced shelves.
If these conditions cannot be respected, the warehouse must be sized to receive the highest load unit and consequently space utilization in the warehouse decreases as the number of load units of a height less than the maximum increases. Besides warehouses where continuously arriving load units are of variable height, the problem of sizing the compartments is particularly severe for example in warehouses for stocking and distributing seasonal products where the height of the load units changes as the products stored change.
A known solution to the problem applicable to both cases is to provide on the side walls of the compartments small brackets, for support of auxiliary pallets and wider than those usually used with the load units, in such a manner as to provide shelving of an intermediate height by resting an auxiliary pallet on the small brackets. Such a solution results in the problem, however, of having to foresee and store ready for use a number of auxiliary pallets equal to the expected maximum number of load units lower than the maximum height. In addition, enlargement of each compartment to allow insertion of load units on normal pallets without interference with the small support brackets considerably diminishes space utilization in the warehouse. Finally, there must be provided means for handling the auxiliary pallets and this increases the cost of the system.
Another known solution to the problem applicable only to the case of seasonal warehouses is the one which provides movable brackets so as to be able to rearrange the warehouse upon each change of season. This solution however involves stopping operations to perform manual positioning and securing of the brackets and this involves great expenditure of time and huge costs.
The general object of the present invention is to obviate the above mentioned drawbacks by providing a warehouse or storage rack with compartments for load units of varying height and handling means for loading and unloading thereof with means for rapidly adjusting the compartment height to the heights of the load units while optimizing utilization of the warehouse volume.